
#ifndef __pref_value_map_h__
#define __pref_value_map_h__

#pragma once

#include <map>
#include <string>
#include <vector>

#include "base/basic_types.h"

namespace base
{
    class Value;
}

// A generic string to value map used by the PrefStore implementations.
class PrefValueMap
{
public:
    typedef std::map<std::string, base::Value*>::iterator iterator;
    typedef std::map<std::string, base::Value*>::const_iterator const_iterator;

    PrefValueMap();
    virtual ~PrefValueMap();

    // Gets the value for |key| and stores it in |value|. Ownership remains with
    // the map. Returns true if a value is present. If not, |value| is not
    // touched.
    bool GetValue(const std::string& key, const base::Value** value) const;
    bool GetValue(const std::string& key, base::Value** value);

    // Sets a new |value| for |key|. Takes ownership of |value|, which must be
    // non-NULL. Returns true if the value changed.
    bool SetValue(const std::string& key, base::Value* value);

    // Removes the value for |key| from the map. Returns true if a value was
    // removed.
    bool RemoveValue(const std::string& key);

    // Clears the map.
    void Clear();

    iterator begin();
    iterator end();
    const_iterator begin() const;
    const_iterator end() const;

    // Gets a boolean value for |key| and stores it in |value|. Returns true if
    // the value was found and of the proper type.
    bool GetBoolean(const std::string& key, bool* value) const;

    // Gets a string value for |key| and stores it in |value|. Returns true if
    // the value was found and of the proper type.
    bool GetString(const std::string& key, std::string* value) const;

    // Sets the value for |key| to the string |value|.
    void SetString(const std::string& key, const std::string& value);

    // Gets an int value for |key| and stores it in |value|. Returns true if
    // the value was found and of the proper type.
    bool GetInteger(const std::string& key, int* value) const;

    // Sets the value for |key| to the int |value|.
    void SetInteger(const std::string& key, const int value);

    // Compares this value map against |other| and stores all key names that have
    // different values in |differing_keys|. This includes keys that are present
    // only in one of the maps.
    void GetDifferingKeys(const PrefValueMap* other,
        std::vector<std::string>* differing_keys) const;

private:
    typedef std::map<std::string, base::Value*> Map;

    Map prefs_;

    DISALLOW_COPY_AND_ASSIGN(PrefValueMap);
};

#endif //__pref_value_map_h__